i guess it;s a matter of preference in the end , but as i said , i don't like them that much.

Between paladins (black knights) , mage armors and advance strategists , i don't see which niche samurais fill. Armored mages are generally heavier on the defense and while their aoe dps is skill dependent , they are straight up better dps during skill use.
Dark knights are very tanky 2 blockers. They don;t clear as fast as samurais , but they can actually tank more then just medium strenght mobs.
And the likes of uzume and shuka can be used easily on the weak mobs that tend to rush and still benefit the team with their skills.